Apparatus for bending an elongated element



March 4, 1969 R. E. ARNOLD 3,430,478

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ATTOR/V-TYS United States Patent 4 Claims ABSTRACT OF THE DISCLOSURE An apparatus having a pair of opposed gear racks engaged upon a central fixed gear, and further having a pair of holders on opposite sides of the central gear for holding the opposite extremities of an elongated element which is to be bent, the holders each including a rack gear engaged upon the gear racks so that rotation of the gear racks about the central fixed gear causes relative longitudinal movement of the gear racks, thereby rotating the rack gears of the holders and bending the element in two places simultaneously, the distance between the bends being governed by the distance between the central gear and the holders, and the degree of bend being determined by the degree of rotation of the gear racks.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to an apparatus for bending an elongated element such as a reinforcing bar, and more particularly to an apparatus adapted to bend an elongated element in two places simultaneously and in such a manner that the extremities of the element outwardly of the bends are characterized by translational movement rather than rotational movement.

Description of the prior art Bending apparatus of the prior art generally includes portions rotatable relative to one another and between which is placed the elongated element to be deformed or bent. The relative rotation of such portions of the apparatus causes one or both extremities of the element to also move rotationtally, that is, in an arcuate path about the bending apparatus. Where the element to be bent is a reinforcing bar many feet in length, the scythe-like action of the bar extremity as it sweeps about the bending apparatus presents a problem to workmen in the area and usurps floor space for other equipment. Moreover, the rotating bar extremity is often of such length that it workman other than the operator of the apparatus.

SUMMARY OF THE INVENTION The present invention deals with the previously mentioned difficulties existent in the prior art by providing an apparatus for bending an elongated element in two places simultaneously, thereby doubling the productivity of the usual single-bend machines of the prior art, the apparatus also being adapted to rotate that portion of the element which is between the two bends so that the extremities of the element move translationally or sideways rather than in a sweeping, rotational movement.

In addition to the foregoing, it is an object of the invention to provide an apparatus of the aforementioned character in which the degree of bend is controlled by the degree of rotation of the portion of the element between the pair of bends therein.

A further object of the invention is the provision of such an apparatus in which the distance between the bends is easily adjustable by merely relocating the hold- 3,430,478 Patented Mar. 4, 1969 ers for the element extremities at different distances from each other.

Yet another object of the invention is to provide an apparatus of the aforementioned character which can be quickly mounted to existing bending apparatus of the type having a central turntable, and which can utilize the turntable rotation for effecting the desired rotation of that portion of the element located between the two bends.

Another object of the invention is the provision of an apparatus of the aforementioned character which utilizes a pair of opposed gear racks in engagement with a fixed central gear to thereby efiect relative longitudinal move ment between the racks upon rotation of the gear racks about the gear, such longitudinal movement, in turn, imparting rotational movement to a pair of rack gears located on either side of the central gear and in engagement with both of the gear racks. Holders for the element to be bent form a part of the rack gears so that as the bends are formed the rod extremities are rotated correspondingly, thereby maintaining the rod extremities in their original direction of extension.

A further object of the invention is the provision of such an apparatus in which the gear racks can be rotated in either direction to thereby form, for example, two 01fset bend sections which together define a channel-shaped bend area.

Other objects and features of the invention will become apparent from consideration of the following description taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the bending apparatus of the present invention, only a portion of the stationary support structure or frame being illustrated for brevity;

FIG. 2 is a view taken along the line 22 of FIG. 1, and also illustrating diagrammatically the location of the drive means for the turntable;

FIGS. 3 through 6 are diagrammatic illustrations of the sequential steps followed in forming a channel-shaped bend area in the element, FIG. 3 illustrating the starting position, FIG. 4 illustrating the completion of the first pair of bends, FIG. 5 illustrating the starting position for the second pair of bends, and FIG. 6 illustrating the completion of the second pair of bends, it being noted that the turntable has been rotated in a direction opposite the direction of rotation for the first pair of bends; and

FIG. 7 is an elevational view of the formed element resulting from the bending operation illustrated in FIGS. 3 through 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, and particularly to FIGS. 1 and 2, there is illustrated an apparatus 10 for bending an elongated element such as a reinforcing bar 12. The reinforcing bar 12 is of that type commonly used in reinforcing concrete structures such as bridges and the like, and the degree and location of the bends is usually particularly specified within relatively close tolerances. Moreover, the bar 12 is often very long and extends laterally or outwardly of the apparatus 10 a considerable distance into adjacent areas of the fabricating shop. As will be seen, the appaartus 10 forms the desired bends in the bar 12 in such a way that the axes of the bar extremities after the bending operation are substantially parallel to their original axial orientation. No sweeping arcuate movement occurs during the bending operaiton, but rather only a translational movement dictated by the extent of the socalled height of slope of the bend area.

The apparatus 10 comprises, generally, a stationary support structure or frame 14; a central toothed element or gear 16 which is fixed in position; a rack structure including an elongated rack mount 18 and a pair of elongated gear racks 20 and 22 which are longitudinally movable or slidable relative to each other on the rack mount 18, the gear racks 20 and 22 also being spaced apart in confronting relation and engaged upon the central gear 16; a pair of holding dogs or holders 24 and 26 on opposite sides of the central gear 16 and adapted to support the opposite extremities of the bar 12, the holders including, respectively, toothed elements or rack gears 28 and 30 in engagement with the pair of gear racks 20 and 22; and a drive mechanism or structure 32 for rotating the rack mount 18 about the central gear 16 to thereby effect relative longitudinal movement of the gear racks 20 and 22 and consequent rotation of the holders 24 and 26 for bending the bar 12 in two places simultaneously.

The frame 14 includes a horizontally oriented plate or worktable 34 characterized by a relatively large, centrally located circular opening which rotatably accommodates a head plate or turntable 36 which forms a part of the drive structure 32. In addition, the support structure or frame 14 includes an elongated bar or support bridge 38 span ning the central opening in the worktable 34 and having its opposite extremities rigidly fastened to the worktable 34 by a plurality of bolts 40. The support bridge 38 extends through the vertical center line of the central opening in the worktable 34 and is spaced above the turntable 36 with a clearance sufiicient to permit free rotation of the turntable 36.

The frame 14 includes a number of other conventional elements which are not illustrated since they form no part of the present invention. For example, a suitable frame 14 would include a floor plate or base and a plurality of upstanding plates, walls, and the like welded or otherwise rigidly secured to the base and to the worktable 34. Since the bending apparatus is subject to comparatively high stresses, the components of the frame 14 are preferably relatively heavy in structure to bear the anticipated loads without appreciable deflection.

The central gear 16 is located with its axis of rotation in alignment with the vertical, rotational axis of the turntable 36, and is rigidly secured to the upper surface of the support bridge 38 by a plurality of usual bolts 42 which extend through the central gear 16, through the circular flange of a spacer bearing 44, and into suitable threaded openings in the support bridge 38. The spacer bearing 44 locates the central gear 16 in position for meshing engagement with the gear racks and 22, and its circular flange extends into a central opening provided in the base of the rack mount 18 to thereby afford a bearing structure about which the rack mount 18 can rotate.

The rack mount 18 is a U-shaped structure constituted of an elongated, horizontally oriented plate or base 46 and a pair of elongated sides 48 and 50 which are welded to the side edges of the base 46 in upstanding, confronting relation. The vertical axis of the central opening in the base 46 is in vertical alignment with the rotational axis of the turntable 36, and the rack mount 18 is freely rotatable about the fixed spacer bearing 44.

Each of the gear racks 20 and 22 is characterized by a series of vertically oriented and longitudinally arranged teeth have a pitch permitting smooth meshing with the gear teeth of the central gear 16 and the rack gears 28 and 30, as will be seen. In addition, the pitch diameters of the rack gears 28 and and the central gear 16 are the same so that rotation of the rack gears 28 and 30 exactly corresponds to the rotation of the gear racks 20 and 22 about the central gear 16.

The sides of the gear racks 20 and 22 are freely slidable upon the adjacent surfaces of the rack mount sides 48 and 50, and the bases of the gear racks 20 and 22 are freely slidable upon the upper surface of the rack mount base 46. Accordingly, upon rotation of the rack-mount 18 about the fixed central gear 16, the gear racks 20 and 22 are slidably movable in opposite directions relative to one another.

Such relative slidable longitudinal movement of the gear racks 20 and 22 effects a corresponding rotation of the rack gears 28 and 30. That is, the gear teeth of each of the rack gears 28 and 30 are characterized by a pitch which is the same as that of the central gear 16 and the gear racks 20 and 22. Thus, upon rotation of the rack mount 18 in a clockwise direction, as viewed in FIG. 4, both of the rack gears 28 and 30 will move in a counterclockwise direction.

The rack gears 28 and 30 constitute an integral part of the holders 24 and 26, respectively, the holder portion and the gear portion being welded or otherwise rigidly secured together. Each holder portion includes a pair of jaws 52 which are spaced apart to define a slot or passage wide enough to accommodate the diameter of the bar 12, and the inwardly oriented ends of the pair of jaws 52 are flared or outwardly curved to form a divergent section which facilitates formation of smooth bends in the bar 12.

The drive structure 32 may be any suitable means for rotating the rack mount 18, but preferably includes the turntable 36, a drive shaft 54 connected to the turntable 36, and an electric motor or other conventional drive means which can be operated forwardly or reversely to thereby drive the turntable 36 in either a clockwise or a counterclockwise direction. Moreover, the drive means preferably is one which is capable of closely controlling the degree of rotational movement of the turntable to thereby closely control the angle or degree of the bends formed.

Rotational movement of the turntable 36 by the drive means is imparted to the rack mount 18 by means of a pin or thrust member 56 which is slidably fitted or placed within a suitable opening in the turntable 36. The member 56 is preferably cylindrical in configuration with its circumferential surface extending upwardly sufiiciently to engage the outer face of one or the other of the rack mount sides 48 and 50. If desired, a number of openings can be placed in the surface of the turntable 36 at various distances from the rotational axis of the turntable 36 to locate the member 56 in optimum position for the particular drive means and for the particular drive means control system employed.

A typical operation of the bending apparatus 10 is illustrated in FIGS. 3 through 7, the sequence of steps shown being effective to bend or deform the bar 12 into the channel-shaped configuration seen in FIG. 7. The bending operation is begun by inserting the member 56 in position for engagement with the rack mount side 48 as shown in FIG. 3. The drive means is next operated to rotate the turntable 36, engage the member 56 against the rack mount 18, and thereby rotate the rack mount 18 in a clockwise direction. Since the central gear 16 is fixed, a corresponding longitudinal movement of the gear racks 20 and 22 occurs, the rack 20 moving to the left and the rack 22 moving to the right, as viewed in FIGS. 3 and 4. The longitudinal movement of the racks 20 and 22 effects a corresponding counterclockwise rotation of the holders 24 and 26 to form a pair of bends simultaneously in the bar 12. During the bending operation the axes of the bar extremities remain parallel to each other and to their original axial orientation, the bar extremities merely being translated, rather than rotated.

Pearls; The resulting shape of the bar 12 is illustrated in From the foregoing, it is seen that the bending apparatus is adapted to simultaneously form two bends, and that the bar extremities are not rotated about the turntable, but rather the portion of the bar between the pair of bonds is rotated. The bar extremities remain essentially parallel to their original positions throughout the bending operation. The extent or degree of the bends in the bar 12 is controlled by controlling the degree of rotational movement of the turntable 36. The distance between the pair of bends, sometimes referred to as the length of slope is controlled by the distance between the holders 24 and 26. This distance is easily adjusted as desired by lifting the rack gears 28 and 30 out of engagement with the gear racks and 22, and reinserting the gears in mesh with the racks 20 and 22 at the desired distance. Greater slope lengths can be provided by making the rack mount 1-8 and the racks 20 and 22 of greater length, provided the drive means is also made sufliciently powerful to generate the necessary torque.

Various modifications and changes may be made with regard to the foregoing detailed description without departing from the spirit of the invention or the scope of the following claims.

I claim:

1. Apparatus for bending an elongated element such as a reinforcing bar, said apparatus comprising:

stationary support means;

a central gear fixed to said support means;

rack means, including a pair of elongated gear racks longitudinally movable relative to each other, said gear racks being spaced apart in confronting relation and engaged upon said central gear;

a pair of holders on opposite sides of said central gear adapted to support the opposite extremities of the elongated element to be bent, each of said holders including a rack gear in engagement with said pair of gear racks;

and means including an element engageable with said rack means, and operative to rotate said rack means about said central gear to thereby etfect relative longitudinal movement of said gear racks whereby said pair of holders rotate for bending of the elongated element.

2. Apparatus according to claim 1 wherein the rack gears of said holders are axially slidably movable into and out of meshing engagement with said gear racks whereby the distance between said holders and consequently the distance between bends in the elongated element can be adjusted prior to the bending operation.

3. Apparatus according to claim 1 wherein said stationary support means includes a fixed frame and a support bridge secured to said frame and underlying said central gear, and wherein said means engageable with said rack means includes a rotatable turntable underlying said support bridge and mounting said element for engagement with said rack means upon rotation of said turntable whereby said rack means and said gear racks are rotated.

4 Apparatus according to claim 1 wherein said rack means includes an elongated rack mount supporting said gear racks for longitudinally slida ble movement.

References Cited UNITED STATES PATENTS 996,064 6/1911 Costello 72-298 CHARLES W. LANHAM, Primary Examiner.

R. D. GREFE, Assistant Examiner.

US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,430,478 March 4, 1969 Ray E. Arnold It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, between lines 52 and 53 insert must be "walked about the bending apparatus by a Signed and sealed this 31st day of March 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

